It is desirable in a great number of biomedical fields to be able to provide controlled release of bioactive agents into body tissues or fluids. However, due to the multiplicity of the types of chemical structures of bioactive agents, the desired time-release profile for a particular bioactive agent, and the diffusion rates in available and desirable substrates and/or bioerosion of such substrates in bodily fluids, it can be difficult to determine the proper combination of substrate/bioactive agent for a suitable time-release profile, if any. In addition, it would be desirable in some cases to have a substrate in a particular shape, such as a lens for use as an ocular insert for treatment of corneal transplant trauma.
It is thus an object of the present inventions to provide a method for making collagen and collagen-like substrates which are adapted through cross-linking for time-release profiles of bioactive agents.
It is a particular object of the present invention to provide ocular inserts whereby the outer surface of the ocular insert is protected against excessive dehydration by cross-linking while the inner surface of the insert is relatively uncrosslinked to allow for the release of the bioactive agent into the tear fluid.
These and other objects of the invention will be apparent from the following description of the invention, the appended claims and from practice of the invention.